1. Field of the Invention
The invention relates to a shock absorber strut with a steering knuckle. More particularly, the present invention is a shock absorber strut in which a steering knuckle forms a reliable connection to the tubular body by a clamping means and a positioning means, where the positioning means includes a projection and a stop.
2. Description of the Related Art
German reference DE 198 15 215 A1 discloses a shock absorber strut with a steering knuckle. The shock absorber strut has a tubular body. A screw connection fastens the steering knuckle to the tubular body. The steering knuckle has a continuous slot which, together with fastening means, forms a clamping connection to the tubular body. A positioning connection having a projection and a recess is between the tubular body and the steering knuckle. The positioning connection makes it possible for the components forming the clamping connection to be perfectly aligned with one another in the circumferential direction. The tubular body has a stop which positions the steering knuckle along the longitudinal axis of the shock absorber strut.
A clamping connection must be reliable so that the steering knuckle cannot come loose under any circumstances. The tightening torque needed to obtain a high clamping force requires clamping screws capable of being subjected to high load. The tubular body is also subjected to considerable load, namely the amount of clamping force or load required to ensure a secure connection.
The object of the present invention is to produce a shock absorber strut which provides the necessary orientation of a clamping connection of the strut to a load bearing part by fixing the steering knuckle in the axial direction of the shock absorber strut. The object is achieved by a one piece component of a projection of the positioning device and a stop for positioning the steering knuckle along the longitudinal axis of the tubular body.
In the present invention, a projection fastened to the tubular body need only absorb circumferential forces during assembly. However, if the clamping connection of the steering knuckle comes loose while the shock absorber strut is in use, the force of the connection between the projection and the tubular body is then also available for the stop in order to absorb the force of loads in the longitudinal direction.
In a further embodiment, the stop has a middle part which is fastened to the tubular body, and at least one lateral wing extends from the middle part and is designed so as to be at a radial distance from the tubular body. It has proved beneficial if the middle part has two wings, to avoid introducing any torsional forces into the connection between the middle part and the tubular body. Furthermore, a larger bearing surface is available for the steering knuckle.
According to another embodiment, the projection is formed by a tongue which is shaped out of the plane of the middle part. It was found that, when the projection engages into the slot of the steering knuckle at a greater radial distance from the tubular body, higher positioning accuracy is achieved or, conversely, a greater dimensional tolerance in the components used can be permitted.
At the same time, the projection has an S-shaped profile. This embodiment is advantageous in two respects. On the one hand, forming achieves strain hardening which makes it possible for the projection to have a relatively small wall thickness. Furthermore, the outlay in terms of material even for the length of the tongue is more advantageous than that for a simply vertical projection.
For shock absorbers struts subjected to particularly high stress, the projection has a U-shaped profile. The two limbs extending essentially perpendicularly to the longitudinal axis of the shock absorber strut then engage into the slot of the steering knuckle.
In a related embodiment, the projection has a double-layered design essentially at right angles to the longitudinal axis of the tubular body. It is ultimately an axially compressed Uprofile, in which the axial web has been pressed together so that the two vertical webs come to bear or be in contact at least over a region of length.
In the embodiment having the tongue, it has proved advantageous if the end face of the projection is at a distance from the tubular body. No defects can form during the lacquering operation from failure of lacquer to penetrate a gap.
Regarding fastening the structural unit composed of the stop and of the projection, it is advantageous if the middle part is connected for positioning to the tubular body by means of contact welding. Contact welding is resistance welding which is executed in a central region of the middle part, and therefore the edges of the middle part remain available for further fastening possibilities.
It is therefore possible for the middle part to be connected to the tubular body by means of fastening welding in addition to the contact welding. With fastening welding, there is a high degree of flexibility regarding the type of welding method to be used. Even when heat is generated on one side, the middle part cannot separate from the tubular body due to the fastening weld.
In order to simplify the welding apparatus and to increase the contact surface for contact welding, the middle part makes a positive connection with the tubular body. For this purpose, the tubular body has a depression into which a bead of the middle part engages for creating a positive connection.
For shock absorber struts subjected to greater stress, at least one wing may be welded to the tubular body. This embodiment may also be combined with fastening welding of the middle part. A longer weld seam is obtained, which can consequently also transmit higher load.
To allow free choice of the welding method, the wing has a surface of contact with the tubular body. To make the contact surface readily accessible to the welding apparatus, the contact surface is formed on the lateral edge of the wing. It was found to be particularly advantageous if the contact surface is formed by the end face of the lateral edge. The ratio of the outlay in forming relates to the increase in consolidation and is particularly favorable.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.